Portable threading device



1932' H. M. QLMSTEAD 1,871,732

PORTABLE THREADING DEVICE Filed May 24. 1930 Patented Aug. 16, 1932 HARVEYVM. QLMSTEAD, or, nnlvvn'n; oononAno PORTABLE THREAIJING DEVICE W 7 Application filed May 24, 1930. Serial No. 455,317.

This invention relates to an attachment for portable electric drills so as to adapt them for threading pipe or other threading purposes. :The principal objectof the invention is to provide a simple and efiicient attach-' ment which can be quickly and easily applied to or detached from a portable electric drill so that the drill motor can be employed for rotating the threading die. I j Another object of the invention is to so construct the device that dies of various sizes, threads, etc., can be quickly and easily inter- .changed. V I

7. Other objects and advantages reside in the detail construction of the inventiomwhich is designed for simplicity,economy, and efiiciency. These will become more apparent from the following description.

In the following detailed description of.

the invention reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the descripp 1 dium of an adaptor illustrated in detall in tion.- 7

In the drawing: I

Fig. 1 is a side elevation of the invention applied to a portable electric drill. In this view the gear box cover plate has been partially broken away to showthe interiorconstruction.

Fig. 2 is a plane view of the complete device of Fig. 1.

Fig. 3 is an enlarged vertical section through the gear box, taken on the line 33, Fig. 1.

Fig. 4 is a detail view of what might be termed the adapter for connecting the mechanism of this invention with the drill chuck.

In the drawing the motor of a typical portable electric drill has been illustrated at 10 with its feed cable at 11, gear casing at 12, and drill chuck at 13. The drill is preferably of the type having a reversible electric motor provided with a manually operated reversing switch such as indicated at 1 1.

The invention comprises a gear box 15 covered by means of a cover plate 16 secured thereon with suitable attachment screws 17. The gear box 15 encloses a worm gear 18 in mesh with a worm 19. The worm gear 18 is with a plurality of sector-shaped teeth 30.

formed with a hollow trunnion 20 which extendsthrough the back ofthe gear box 15' and the cover plate 16 so asto form journals or bearings for the worm gear. The worm 19 is keyed on a worm shaft 21 which extends through one side of the gear box terminating in a clutch member'22. 1 The other. extremity of the worm shaft 21 is preferably carried in a bearing on a removable cap 23.

The entire .gear box issecured to the exdo tremities of a U-shaped frame member. 24,,Y which extends rearwardly to form a cradle forthedrill'motor 10, terminating in a re duced' or handle portion 25. i ,The drill motor. 10 is secured in place in the cradle formed by the frame member 24 by means of a clamping band 26,-the extremitiesof which may be drawn together by means of. a clamp bolt 27 tocause the band to tightly grip thedrill mov V tor 10. The tongue of'the gear box is ab- .70 sorbed in angle. braces 31 which extend between the box and the frame member 24'.

The power is transmited through theme Fig. l. The adaptor comprises a stem 28 of a size to be conveniently placed into. and clamped by the drill chuck 13, similarly to the manner of clamping a'drill in the chuck. The stem 28 terminates in ahead 29 provided The teeth 30 pass-into the spaces between the teeth ofa co-acting clutch'member 22 of similar construction, to the head 29. The teeth '30 are so formed that there will be a slight amount of play at this point so that the members 22 and 29 not only form a tooth clutch but also a universal joint, to accommodate any misalignmentin the positioning of the motor 10.

The 'threadcutting die may be secured to the'worm gear 18 in'any desired manner. A very satisfactory-method of accomplishing this is illustrated in the drawing, in which a cylindrical stock 32' passes a completely through the trunnion 20 0f the gear 18. The stock 32 carries a square die socket 33 at its one extremity closed by means of a pivoted cover plate 34. The die socket 33 is adapted to receive a square die 35 of the type known as a Reed die.- The cover plate .34 is piv- 1.00

. each-side. efsaid' portable drill to align the oted on a pivot screw 36 at one corner and secured by means of a wing nut at the opposite corner. By loosening the wing nut 37 the cover plate 34. may be rotated about the pivot screw 36 so as to allow the die 35 to' be easily removed from the socket 33.

The stock 32 may be secured to the worm gear 18in any desired mannerlsuch as bythreading a set screw 38 into the joint between the die and gear as illustrated. A're-v ducing sleeve 39 may besecImedjn-theopposite end of thepdie 38 by means of a set screw 40 when it is desired to thread smaller pipe than the interior diameter of the die.. In use, the stock is slipped overt-he ex tremityof a pipe :or rodandthe motorstarted injthe forward direction. When the desiredv length of "thread has been cut, the... reversing switch. 14 is. operated'to reverse the motoriand back thedie from the thread ll hen the threading operations have been completed the motor 1 0 canqbe quickly released by loesening the clamp screw 27 so thatthe drill may beused' for. other purposesm i v 7 While a specific) form of the improvement has been. described and. illustrated herein, it

is desired te be understood that the'same may" beyaried within the scopeof theappended claims without departing from, the spirit of the invention.

Havingthus described the invention, whatis claimed 1 and. desired secured: by Letters- Patent is:

)1. A threading attachmentfor portable electricirdrills compr1s1ng;qargear box; a. worm-gear oarnalled 1n-sa1d gear box; a.

pipe threading. die operatively' connected to said worm geanandspositioned on the ex-' tenor of said. gear box; .a'worm- -shaft ex tendinglaterally of "Sal-Cl worm geanand projecting from said-gearbox; means for connecting said worm shaft. to: the; shaft of a portabledrill; a; U-shaped frame securedatt its" extremities to opposite sides :of said.

gear box and extending; rearwardly along latter with said warm; and a clamping band arranged to hold saidportable drill in said- U-shaped frame member.;

2. A threading attachment for portable electric drills-comprising: a. gear. 'box; a v

worm; gear journalled in said gea-ribex; a

pipe threading die operatively connected to said worm gear and positioned'on: the'exterior of said gear a worm shaftextending laterally of said worm gear and }]-IO]60t1'fl;"fI'OD1-' said gear box; means" for connecting-said worm' shaft-v to the shaft of apertable drill a Ueshapedframe secured,

atits extremitiesito oppositesides of said gear box and extending rearwardly along each side of. said-portable drillto align the latter with said-worm; a clamping band arranged to. hold said portable drill, in said U-shaped frame member; and an angle brace extending from each side of said U-shaped frame to opposite sides of said gear box to rigidly maintain said worm in alignment with said portable drill.

3. A threading attachment for portable latter. with..said1worm.;.. apccla'mping band arranged to hold saidfportable drill in said U-shaped frame. member; and av handle. formed on, said .ueshaped frame .Jat .the rear of saidflportable drill. f l r 4;. A"threading...attachment, for portable.

electric drills.,.comprising;. a gear box; .a'

worm gear. journa-lledflin, said gear box;...a. pipe threading die operatively' connected to said worm gear and positioned on theexterionof said gear. box; a. worm shaft -.extendingjlaterally ofssaid worm gearand projecting from saidgear. box; means. for. connectingsaid worm shaft to the: shaft of,

a portable drill; a'Ui-shaped frame secured electric drills comprisin a/gear. box; a

at. itsv extremities. to. opposite sides of said gearboxyand extending. rearwardly alongv each sidefof said. portable drillto align the.

latter with; said. worm; a clampingiband; arranged to, hold said portable drill in said U-shapedframe member; a handle'forined.

on said U-shaped frame at .the rear ofsaid' p0rtable...drill, said handle comprisinga narrowedjre'arwardly' prejectingportion of said frame.

In testimony ,whereofl'atfix my signature.

"HARVEY M. OLMSTEAD; 

